Circuit-interrupting device



SeptT 25, 1945.

H. .E. sTRANG E'rAL CIRCUIT- INTERRUPTING DEVICE n Filed kann 2o, 1942 ,.e, m @RL m o M J .w tE, t ...A @ma .W www@ Wm WM LMT and forming a part of this application.

' Patented se'|n. 2f5,1945A A 2,385,658 CIRCUIT-INTERRUPTING DEVICE Harold-E. Strang, A rdmor per Darby, and Leonar e, George M. Reed, Up-

J. Linde, Drexel Hill,

Pa., assignors to General Electric Company, a corporation of New York Application March 20, 1942, Serial No. 435,464

Our invention relates to circuit-interrupting devices and more particularly to a circuit interrupter which includes as a part of its physical structure a second circuit-interrupting device preferably of the type including a fusible ele- 5 ment.

. In the oopendmg application of Alan G. Darling, Serial No. 428,739, filed January 29, 1942, now Patent No. 2,358,215, issued September 12, 1944,

and assigned to the same assignee as the present application, there is disclosed and claimed a switching device or circuit interrupter including a current-limiting fuse connected in series therewith, which serially arranged combination produces certain very desirable results in connection 1'5 with the protection of an associated device or system. Recently, there has been a great demand for the standardization of switchgear which has been accomplished by the use of so-called It would -be desirable "metal-clad switchgear. to provide the advantages of the series arrangement of circuit breaker and current-limiting fuse which would lit in Iwith the standardized switchgear .without requiring additional' space together with a greatly increased cost. f

Accordingly, it is an objectof our invention to provide a new and improved circuit-interruptlng device in which a circuit interrupter of any standard type includes as a part of its physical structure a second circuit-interrupting device electrically in series with the first-mentioned circuit interrupter.

AIt is another obiect of our invention to provide a circuit-interrupting device including a circuit breaker having as a part of its physical structure a current-limiting fuse serially connected with the circuit-breaker contacts for interrupting fault currentsv above the range of operation of the first-mentioned circuit interrupter.

7 Claims. (Cl. 200-114) oil circuit breakers, air-blast circuit breakers, and the like. It is, however, particularly applicable to switchgear which comprises a stationary housing into which electric power circuits are connected, which power circuits are controlled by a cooperating electric circuit breaker mounted on a removable unit which may be of the vertical lift or .the horizontal drawout type. Movement of the unit including the circuit breaker into and out of the stationary housing connects the circuit-interrupting device with the associated power circuit through primary disconnecting devices which usually comprise stationary portions in the housing and cooperating conductor studs on the circuit breaker. y

Referring now to Fig, 1, we have illustrated a single-line diagram of a. power bus I 0 and a feeder circuit II which terminate in a stationary metal housing generally indicated at 12 and the ends of which are connected to the stationary portions I3 and I4 respectively of so-called "primary disconnecting devices. 'I'he connection between bus I0 and feeder circuit II is controlled by means of any well-known type of circuit interrupter unit generally indicated at I5, which is constructed for movement into and out of stationary housing I2. Circuit breaker I5 comprises schematically illustrated conductor studs I6 and Il Yincluding cooperating portions for respectively engaging with the stationary portions I3 and I4 of the primary disconnecting devices.

Circuit breaker unit I5 is schematically lllustrated as comprising a circuit breaker of the latched closed type including a movable conducting member ,-I8 for completing a circuit between the lower ends of conductor studs I 6 and I1. -A suitable trip coil I9 for releasing latch 20 is provided and trip coil I 9 is connected in a suitable control circuit through a switch 2| Further objects and advantages of lour invendo which is closed when the circuit breaker is tion will become apparent as the following description proceeds and the featuresof novelty which characterize our invention will be pointed out with particularity in the claims annexed to Y For a better understanding of our invention, A reference may be had to the accompanying` drawing in which Fig. y 1 is a schematic diagram of a power system employing a circuit-interruptmg device embodying our invention, Fig. 2 ais- 50 closes a side elevational view of a well-known type of standard air circuit breaker embodying our invention constructed for use with metalclad switchgear of the vertical lift type, Fig. :ll is an enlarged sectional view of a portioniof Fig. 2, and Fig. 4 is a view similar to Fig. 3 illustrating a modiiication of our invention.

It will be understood that our invention is applicable to any circuit-interrupting devices and, when applied to a circuit breaker, is' appli- 60 cable to any of the well-known types,` such as In Fig.

automatically through the operation lof an overcurrent relay schematically indicated at 22, which 5- controls the energization of trip coil I9. Relay 22 .is energized from a suitable current transformer 23 connected in feeder circuit II. ,Manual opening of circuit breaker I5 is obtained by. operation of opening switch 24 connected in series with trip coil I9. The operation of circuit breaker unit I5 for controlling the flow of power between bus Il) and feeder circuit II will be obvious to those skilled in the art. In order to interrupt the now of current between bus III and feeder circuit I I when the current flowing is above that which can safely be interrupted by circuit breaker I5, we connect in series with thev relatively movable contacts of circuit breaker I5 a current-limiting fuse 25 which forms a part of the physical structure of circuit breaker I5.

1, the current-limiting fuse or circuitalso be understood by `actually be current-limiting vention will be, in so enclosure or cubicle, not shown interrupting device 25 is indicated as comprising the circuit-breaker stud I6 but it will be apparent from the following description that it could the present standardized forms of switchgear which are so much in demand.

Although we have disclosed a current-limiting fuse 25 as comprising the stud I6 of circuit breaker i5, it should be understood that it might equally well comprise the stud Il instead, in the event that circuit Il were a supply circuit rather than a feeder circuit since it might be desirable to have the current-limiting fuse on the so-called hot side of the circuit breaker unit. Also two fuses, one in eachA stud might be provided. It will those skilled in the art that, although circuit breaker unit I has been indicated as controlling only a single-phase circuit, it could equally Well control a polyphase circuit, such as the standard three-phase circuit, in which case, three studs I6and three studs -I1 would be provided and, dependingl upon whether circuit it were a feeder Acircuit ora supply circuit, one or more sets of these conductor studs would fuses serving as the studs of the circuit breaker. l

Although we have specifically referred to fuse 25 asa current-limitingfuse which is preferably 0i the form and construction shown in United lStates Letters Patent 2,188,816 Rankin, assigned to the same assignee as the present application, it might in certain cases be desirable that some other type of circuit-interrupting device, whether of the fusible type or not, be employedin accordance with the present where advantageous results such as those disclosed in the copending- Darling application referred to above are obtained.

Referring now to Figs. 2 and 3, we have disclosed, our invention as specifically applicable to invention but is copending application of Leonard J. I Iindazlerial` to I2 schematically indicated in Fig. 1. More' specifically, the circuit breaker unit of Figs. 2

and 3 comprises a main supporting frame 26 for the movable contact structure which comprises a fixed or stationary contact 2l and a relatively movable contact 23 pivotally mounted at 29 to a. conducting member 30. Conducting Vmember 30 is supported from supporting frame 26 by meansA of an insulating member 3I. Relative movement of movable contact 28. is obtained through the operation or any suitable actuating mechanism, such as supporting frame 26 which may be of the solenoid type, for example. The actuating mechanism 32 is interconnected in any suitable manner movable contact 28, as for example, by link 33 and crank 33. contacts 2l and 28 forms no par-t vof the present disclosed and claimed in the No. 435,463, now Patent 2,335,068, filed March 20,

` type disclosed in conducting member 3.0

invention, particularly a well-known form of air circuit breaker suchl as 1, we schematically illus-f 2 and 3 showing specific applications of our inportions I3 and I4 of Ati-ated as of the well-known vertical lift type, v wherein disconnection of the primary disconnecting contacts is veffected merely by bodily lowering of the circuit-breaker unit I5. As was pointed out in connection with Fig. 1, Ithe circuit-breaker unit IIS wou1d, be housed in aj, grounded metal far as possible, designated by the same reference numerals as in Fig. 1.

in Fig. ,2, similar to the stationary 'circuits 1942, and assigned to the same assignee as the lpresent application.

The stationary contact 2l is electrically connected Ito the lower end of conductor stud I'I lwhile the conducting member 30 pivotally supporting moving contact 28 is electrically connected to the lower end of conducting' stud I6, which not only serves as a, conducting stud but actually comprises the above-mentioned IRankinpatent with the upper ferrule 25 of the fuse being f modified slightly to accommodate the member 35 which serves as the plug-type disconnect contact for the circuit-breaker unit I5 and which is identical with the member 35 associated with conductor stud I1. Electrical connection between -the lower end of current-limiting fuse 25 and may be accomplished in any suitable manner,\,such, for example, an annular spring-type contact member 36 for making electrical contact with the lower ferrule 25" of current-limiting fuse 25. A suitable support 31 either integral with member 30 or `bolted thereto as shown in Fig: 3 may downward movement of current-limiting fuse25 to determine the vertical position thereof.

In order properly to position current-limiting fuse 25 satisfactorily to act as conductor st'ud I6, we provide an may be suitably connected or attached to the body or casing ofcurrent-limiting' fuse 25 intermediate the ends thereof'as by cementing or the like. Collar 33 is provided with a horizontal flange 33 which is adapted to close completely vtheopening 40in supporting frame 26 which accommodates the stud I6 comprising currentlimiting fuse 25 and, furthermore, flange 39 may be bolted or otherwise suitably attached-to supsatisfactory for use in controlling the inter-confeeder circuit or supply circuit and have disclosed our invention' in which the current-limiting fuse comprises the conductor stud of a circuit breaker, it 4 should be understoodthat' it might equally well comprise .some other physical part of the' circuit 32 (Fig. 2), carried by the with The particular construction ofl a current-hunting fuse of the be provided to limit the` annular supporting collar 38 which above, thev currentl ranged therewith in so far as t trated and we intend in the as to comprise movable or pivoted blade 28a. As

illustrated in Fig. 4, aconducting pivoted at 29' to the lower end Member 28 is connected to the contacting portion 28 of movable lblade 28a asby suitable insulating supports 4I and the electrical connection between members 28' and 28 is completed through current-limiting fuse 25a, as is clearly indicated in Fig. 4.

member 28' is of conductor stud From the above discussion, it will be obvious that we have provided a circuit-interrupting device which includes as a physical part thereof a second circuit-interrupting device serially are electrical circuit is concerned. The main circuit-interrupting device operates as a conventional circuit breaker but, in the event of fault currents. greater than those which the circuit breaker can satisfactorily interrupt, the second circuit interrupterbecomes effective to interrupt the current. By this arrangement, a very compact structure isprovided having all of the advantages of a serially arranged current-limiting fuse and circuit-interrupting device.

While we have disclosed certain specific embodiments of our invention, it should be understood that our invention is not limited to the speclflc details and arrangement thereof herein illusappended claims to cover all such changes and modifications as fall within the true spirit and scope of our invention.

What we claim as new and desire to secure by Letters Patent ofthe United States is:

1. In an electric circuit interrupter, a pair oi' relatively movable contacts adapted to be connected in an associated vpower circuit, motive means rfor producing relative separation of said contacts to interrupt the current-,flowing in said associated circuit, and a fuse yof the current- -limiting type wholly replacing a part of the physical structure of said circuit interrupter serially arranged with said relatively movable contacts to interrupt the current flowing in said associated circuit in the event of a fault current above the value capable of being satisfactorily interrupted by said circuit interrupter.

2. In an electric circuit interrupter, a pair of relatively movable contacts for making and breaking an electric circuit through said circuit interrupter, a pair of insulated conductors each connected to one of said relatively movable contacts and each constructed so as to form a stud forconnection with an associated electric circuit, one of said studs comprising a current-limiting fuse so as to provide means for interrupting fault currents above the value capable of being safely interrupted by the relatively movable contacts of .said circuit interrupter.

3. In an electric circuit breaker, a pair of/relatively movable contacts for making and breaking van electric circuit through which said circuit breaker means for initiating relative separation of said contacts in response to the current flowing in an associated electric circuit, and a fuse l current flowing in an associated electric circuit,

` cuit, at least one of said contacts each of which is of the current-limiting type wholly replacing a part of the physical structure of said circuit breaker serially arranged with said relatively movable contacts to interrupt the current llowing in said associated circuit in the event of a fault current on said circuit above the value capable of being satisfactorily interrupted by said circuit interrupter.

4. In an electric circuit breaker, a stationary contact, a movable contact, and means for initiating opening movement of said movable Y' current flowing in an said movable contact current-limiting type vbreaker to interrupt the current flowing in said associated circuit in the event of a fault current on said circuit above the value capable of being satisfactorily interrupted by said circuit interrupter.

5. In an electric circuit interrupter, a pair of relatively movable contacts for controlling the a conductor stud having one end connected to one of said relatively movable contacts and the' other end adapted to be connected with said` associated electric circuit, a second conductor stud comprising a current-limiting fuse having one end thereof connected to the other of said relatively movable contacts while the other end thereof is adapted to be connected with said associated electric circuit, said current-limiting fuse providing means for interrupting fault currents above the value capable of being safely interrupted bythe relatively movable contacts of said circuit interrupter, and means permitting removal and replacement of said conductor stud comprising said current-limiting fuse.

6. In combination with electric switchgear, a

stationary housingI and a removable unit including a circuitbreaker mounted thereon, a pair of conductor studs on said removable unit, each including a portion of the primary disconnecting devices, the other portion of the primary disconnecting device being associated With said stationary housing, a pair of relatively movable connected to the end of one of said conductor studs, said relatively movable contacts being capable of interrupting the current flowing in an associated electric circonductor studs comprising a current-limiting fuse for interrupting fault currents on said associated circuit above the value capable of being safely interrupted by the relatively movable contacts of said circuit breaker, and means permitting ready removal and replacement 'of said conductor stud comprising said current-limiting fuse. y

7; In an electric circuit interrupter, a pair of relatively movable Acontacts for making and breaking an electric circuit through said circuit interrupter,7^ and a pair of insulated conductors each connected to one of said relatively movable contacts and each constructed so as to form a stud for connection with an associated electric circuit, one of said studs comprising a high speed fuse so as to provide means for interrupting fault currents above the value capable of being safely interrupted by the relatively movable contacts of said circuit interrupter.

HAROLD E. STRANO. GEORGE M. REED. LEONARD J. LINDE.

circuit including said f 

